Computer-controlled system for ISEs automatic calibration

摘要

The present work examines the problems encountered during the design, construction and testing of a fully computer-controlled system for automatic calibration of ion-selective electrodes (ISEs), based on two data acquisition boards, a home-made fast multifunction potentiostat, two peristaltic pumps and an injection valve. With few minor modifications, the experimental setup allows the using of batch and flow techniques for automatic calibration of ISEs, operated in potentiometric or amperometric mode. For flow measurements, a wall-jet cell (WJC) was designed, built and characterized. Using [Fe(CN)_6]~(3-)/[Fe(CN)_6]~(4-) as standard redox couple, the WJC amperometric response was examined in order to establish the dispersion factor as well as the hydrodynamic regime as a function of the flow rate and cell geometry. Finally, a Na~+-selective electrode, based on a commercial NASICON (CERAMATEC™), was used to evaluate the electroanalytical performances of the experimental setup for potentiometric and amperometric calibration of ISEs using batch, steady-state flow and flow injection measurements.